C140A Fuel Selector Leaking/Seeping

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eagledriver
Posts: 3
Joined: Thu Aug 26, 2021 5:29 pm
Name: Ed
Location: Lubbock TX
Aircraft Type: C140
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C140A Fuel Selector Leaking/Seeping

Post by eagledriver »

During the annual on our C140A, we found the fuel selector is seeping fuel. From the parts listing, I can't tell if there's an o-ring that can be replaced or something else.

Does anyone have experience in rebuilding these fuel selectors or can give me some advice on if it is rebuildable and if complicated, who might be a good lead for rebuilding it.
Thanks
Ed
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6183
Posts: 369
Joined: Tue May 01, 2018 7:00 am
Name: Mike Smith
Location: Florida
Aircraft Type: 140A (2) 1949 & 1950
Occupation-Interests: Retired aerial power line patrol pilot for Gulf Power Co. CFIA, CFII, MEI
120-140 Assoc. Florida Rep. N9633A & N9688A
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Re: C140A Fuel Selector Leaking/Seeping

Post by 6183 »

Hello Ed,
Fuel valve utilized in the 140A is not complicated at all. There is a packing, p/n 0413020-4 (#17 in the parts book) on the valve shaft (#27). If memory serves me correctly an MS29513-109 o-ring is utilized as a replacement.

In order to replace the packing/o-ring do the following
(1) drain the fuel tanks
(2) remove the selector handle (#26).
(3) remove the bracket (#37) to gain access the center nut on the top of the valve.
(4) place some absorbent rags under the valve to catch any fuel that leaks out when the top is removed.

Be careful when removing the nut to gain access to the packing, there’s a small cup (#18) being pushed upward by a spring (#19) on the shaft. That spring pushes up on the packing/o-ring to make a seal where the shaft comes out of the top of the nut.

Take a look at this also https://www.cessna120140.com/Forum2018/ ... f=7&t=2266
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